A plate-fin heat exchanger generally includes baffles, fins, sealing strips, and deflectors. The fins, the deflectors and the sealing strips are arranged between two adjacent baffles to form a sandwich layer which is a channel. Multiple sandwich layers are overlapped in various manners according to the actual requirements and then are integrated as a whole by brazing, thereby forming a plate bundle. The plate bundle is further assembled with corresponding parts, such as a seal cap, a connecting pipe, a supporting member, to form the plate-fin heat exchanger.
The plate-fin heat exchanger is defined as a heat transmission component including circulating plates and fins. The fins are a key component, and common fins include straight fins, serrated fins, wavy fins, perforated fins and louvered fins. In order to enhance the heat exchange efficiency of the plate-fin heat exchanger, continuous developments and improvements have been made to the structure of the fins.
Compared with a conventional heat exchanger, the plate-fin heat exchanger has a reinforced heat exchange surface and a compact structure, and has a light weight since it is generally made of aluminum alloy. The disturbance on fluid caused by the fins continuously destroys the boundary layer of the fluid, and at the same time, the baffles and the fins both have a high heat conductivity, thus the plate-fin heat exchanger has a high efficiency. Therefore, the plate-fin heat exchanger is adaptable and can be used for heat exchange between various fluids and a phase-change heat exchange with state change. By arranging and combining passages, the plate-fin heat exchanger can adapt to various heat exchange conditions, such as a counter flow condition, a cross flow condition, a multi-flow condition, and a multilayer flow condition. The plate-fin heat exchanger can also meet the heat exchange requirement of the large scale equipment through the combination of series connection, parallel connection, and series and parallel connection of units. Currently, the plate-fin heat exchanger is widely used in air separation plant, petrochemical engineering, refrigeration and cryogenic field, automobile and aviation industries, and etc.
The plate-fin heat exchanger has a compact structure and a light weight, and has a limited installation space, thus there is little room for improvement and optimization of the flow channel structure. However, the structural design of fins of the plate-fin heat exchanger is flexible, and can be further improved and optimized. With the increasing of the heat dissipating capacity of the equipment, the heat exchange efficiency of the plate-fin heat exchanger is also required to be increased. Under this background, one of the main research trends is to improve and optimize the structure of fins of the plate-fin heat exchanger, so as to increase the heat exchange efficiency between the fins and high temperature or low temperature media that passes through the fins.
Reference is made to FIG. 1, which is a schematic view showing the structure of a conventional oil cooler. The conventional oil cooler includes multiple plates 1′ and louvered fins 2′ each of which is located between two adjacent plates 1′. The louvered fins 2′ are configured to change the flow direction of the coolant or the heating medium, to destroy the boundary layer thereof to generate turbulence.
A partial structure of the louvered fin 2′ is shown in FIG. 2. The louvered fin 2′ includes multiple fin units 3′. Each fin unit 3′ includes a top portion 4′, a bottom portion 5′ and two symmetrical louvers 6′, 7′. Adjacent fin units 3′ are arranged in parallel and staggered to each other, that is, a space 8′ is formed between two adjacent parallel louvers. When flowing towards the louvers 6′, 7′ of the fin in the direction indicated by the arrow, the coolant or the heating medium will be blocked by the louvers 6′, 7′, thus will be continuously divided in the traverse plane. When the coolant or the heating medium is divided, the boundary layer thereof is destroyed by the louvered fin 2′ continuously, which may generate turbulence on partial plane, and in turn enhances the heat exchange capability of the plate-fin heat exchanger to some extent. However, in the flow dividing process, due to the limitation of the shape of the louvers 6′, 7′ of the fin, the cooling or the heating medium mainly generates lateral turbulence, and generates little longitudinal (i.e., vertical) turbulence.
Thus, it is necessary to improve the conventional technology to solve the above technical problems.